Photoacid generator

ABSTRACT

A photoacid generator compound having Formula (I): 
                         
wherein, EWG, Y, R, and M +  are the same as described in the specification.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to provisional U.S. Application No.62/273,521, filed on Dec. 31, 2015, the content of which is incorporatedherein by reference in its entirety.

FIELD

This invention relates to methide-containing photoacid generator (PAG)compounds.

INTRODUCTION

Known photoresists can provide features having resolution and sizesufficient for many existing commercial applications. However for manyother applications, the need exists for new photoresists that canprovide highly resolved images of sub-micron dimension.

Various attempts have been made to alter the make-up of photoresistcompositions to improve performance of functional properties. Amongother things, a variety of photoactive compounds have been reported foruse in photoresist compositions. See, for example, U.S. Pat. No.7,304,175 and U.S. Patent Application Publication No. 2007/0027336. Inparticular, tailored photoacid generators (PAGs) having controlled aciddiffusion and improved miscibility with polymers are very important tomeet the challenges for resist materials raised by high resolutionlithography. For example, certain defects such as T-topping, footformation and notching may arise in imaged photoresist films if the PAGis not uniformly distributed within the resist film. It is believed thatthe structure of the PAG anion plays a critical role in the overallperformance of a photoresist by affecting the interaction of thephotoacid generator with other photoresist components. Theseinteractions, in turn, have remarkable effects on diffusioncharacteristics of the photogenerated acid. PAG structure and sizegreatly affect the homogenous distribution of the PAG in the photoresistfilm.

In the art, ionic photoacid generator compounds (PAGs), which contain afluorinated alkylsulfonate group have been widely explored. Uponphotochemical decomposition, these PAGs produce an exceptionally strongsulfonic acid (super acid). The manufacturing of alternative organicanions, such as imide anions or methide anions that are substituted withelectron-withdrawing groups have been disclosed. See for example U.S.Pat. Nos. 5,874,616, 5,273,840 and 5,554,664. In particular, an organicanion having the formula (R_(f)SO₂)₂N⁻ or (R_(f)SO₂)₃C⁻, wherein R_(f)is fluorinated alkyl chain, has been used as PAG counter anion. Forexample, the sulfonium salts or iodonium salts of highly fluorinatedimide or methide anion were used as PAG component in 193 nm resistformulations (see for example M. Padmanaban et. al., SPIE, 2003, vol.5039, p. 723). However, the high fluorine content of the above mentionedmethide anion imparts undesired environmental impact due to theirlimited biodegradability. In addition, the hydrophobic fluorinatedchains impart low surface energy which can lead to uneven distributionof the PAG through the depth of the photoresist film. The later PAGnon-homogeneous distribution can severely affect the lithographicimaging outcome. Attempts have been made to enable the use offluorine-free PAGs in photoresist compositions. See, for example, U.S.Pat. No. 7,655,379 and U.S. Patent Application Publication Nos.2009/0176175, 2009/0181319 and 2009/0181320. However, these attempts didnot address critical PAG structural features and physical properties. Inparticular, the prepared PAG anions lack structural features that areessential for reducing the acid diffusion length during lithographicprocessing, such as the incorporation of bulky group or functionalgroups that are prone to non-bonding interactions with other photoresistcomponents. In addition, these PAG anions include fused aromatic orheteroaromatic groups, which are 1) characterized by strong absorptionat deep ultraviolet radiation and 2) render the PAG poorly soluble intypical formulation solvents, particularly in polar solvents such aspropyleneglycol monomethyl ether (PGME) or propyleneglycol monomethylacetate (PGMEA).

Thus, there remains a need for PAG anions that are free ofperfluoralkylsulfonate, that possess certain structural, chemical andphysical characteristics to limit photoacid diffusion rate, providebetter miscibility with other photoresist components, and produce superacid upon photodecomposition.

SUMMARY

An embodiment provides a photoacid generator compound having Formula(I):

wherein:

EWG is an electron-withdrawing group;

Y is a single bond or a linking group;

R is hydrogen, a straight chain or branched C₁₋₂₀ alkyl group, astraight chain or branched C₂₋₂₀ alkenyl group, a monocyclic orpolycyclic C₃₋₂₀ cycloalkyl group, a monocyclic or polycyclic C₃₋₂₀cycloalkenyl group, a monocyclic or polycyclic C₃₋₂₀ heterocycloalkylgroup; a monocyclic or polycyclic C₃₋₂₀ heterocycloalkenyl group; amonocyclic or polycyclic C₆₋₂₀ aryl group, a monocyclic or polycyclicC₁₋₂₀ heteroaryl group, each of which except hydrogen is substituted orunsubstituted; and

M⁺ is an organic sulfonium cation or an organic iodonium cation havingFormula (VII):

wherein,

R⁰ is a C₁₋₂₀ alkyl group, a C₁₋₂₀ fluoroalkyl group, a C₃₋₂₀ cycloalkylgroup, a C₃₋₂₀ fluorocycloalkyl group, a C₂₋₂₀ alkenyl group, a C₂₋₂₀fluoroalkenyl group, a C₆₋₃₀ aryl group, a C₆₋₃₀ fluoroaryl group, aC₁₋₃₀ heteroaryl group, a C₇₋₃₀ aralkyl group, a C₇₋₃₀ fluoroaralkylgroup, a C₂₋₃₀ heteroaralkyl group, or a C₂₋₃₀ fluoroheteroaralkylgroup, each of which is substituted or unsubstituted, and

Ar is a C₆₋₃₀ substituted aromatic organic group,

wherein Ar is optionally connected to R⁰.

Another embodiment provides an acid-sensitive polymer, which is apolymerization product of the photoacid generator compound.

Another embodiment provides a photoresist composition, including anacid-sensitive polymer, a solvent, and the photoacid generator compound.

Another embodiment provides a photoresist composition, including theacid-sensitive polymer and a solvent.

Another embodiment provides a method of forming an electronic device,including: (a) applying a layer of the photoresist composition on asubstrate; (b) patternwise exposing the photoresist composition layer toactivating radiation; and (c) developing the exposed photoresistcomposition layer to provide a resist relief image.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present exemplary embodiments may have different forms and shouldnot be construed as being limited to the descriptions set forth herein.Accordingly, the exemplary embodiments are merely described below, byreferring to the figures, to explain aspects of the present inventiveconcept. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. Expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist.

It will be understood that when an element is referred to as being “on”another element, it can be directly in contact with the other element orintervening elements may be present therebetween. In contrast, when anelement is referred to as being “directly on” another element, there areno intervening elements present.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers, and/or sections, these elements, components, regions,layers, and/or sections should not be limited by these terms. Theseterms are only used to distinguish one element, component, region,layer, or section from another element, component, region, layer, orsection. Thus, a first element, component, region, layer, or sectiondiscussed below could be termed a second element, component, region,layer, or section without departing from the teachings of the presentembodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

As used herein, when a definition is not otherwise provided, the term“alkyl group” refers to a group derived from a straight or branchedchain saturated aliphatic hydrocarbon having the specified number ofcarbon atoms and having a valence of at least one.

As used herein, when a definition is not otherwise provided, the term“fluoroalkyl group” refers to an alkyl group in which at least onehydrogen atom is replaced with a fluorine atom.

As used herein, when a definition is not otherwise provided, the term“alkoxy group” refers to “alkyl-O—”, wherein the term “alkyl” has thesame meaning as described above.

As used herein, when a definition is not otherwise provided, the term“fluoroalkoxy group” refers to an alkoxy group in at least one hydrogenatom is replaced with a fluorine atom.

As used herein, when a definition is not otherwise provided, the term“alkenyl group” refers to a group derived from a straight or branchedchain unsaturated aliphatic hydrocarbon having the specified number ofcarbon atoms and having a valence of at least one.

As used herein, when a definition is not otherwise provided, the term“fluoroalkylene group” refers to an alkylene group in which at least onehydrogen atom is replaced with a fluorine atom.

As used herein, when a definition is not otherwise provided, the term“cycloalkyl group” refers to a monovalent group having one or moresaturated rings in which all ring members are carbon.

As used herein, when a definition is not otherwise provided, the term“fluorocycloalkyl group” refers to a cycloalkyl group in which at leastone hydrogen atom is replaced with a fluorine atom.

As used herein, when a definition is not otherwise provided, the term“heterocycloalkyl group” refers to a monovalent saturated cyclic groupthat has atoms of at least two different elements as members of itsring(s), one of which is carbon.

As used herein, when a definition is not otherwise provided, the term“heterocycloalkyl group” refers to a monovalent unsaturated cyclic groupthat has atoms of at least two different elements as members of itsring(s), one of which is carbon.

As used herein, when a definition is not otherwise provided, the term“aryl”, which is used alone or in combination, refers to an aromatichydrocarbon containing at least one ring and having the specified numberof carbon atoms. The term “aryl” may be construed as including a groupwith an aromatic ring fused to at least one cycloalkyl ring.

As used herein, when a definition is not otherwise provided, the term“fluoroaryl group” refers to an aryl group in which at least onehydrogen atom is replaced with a fluorine atom.

As used herein, when a definition is not otherwise provided, the term“aralkyl group” refers to a substituted or unsubstituted aryl groupcovalently linked to an alkyl group that is linked to a compound,wherein the terms “aryl” and “alkyl” have the same meaning as describedabove.

As used herein, when a definition is not otherwise provided, the term“fluoroaralkyl group” refers to an aralkyl group in which at least onehydrogen atom is replaced with a fluorine atom.

As used herein, when a definition is not otherwise provided, the term“heteroaryl”, which is used alone or in combination, refers to anaromatic hydrocarbon containing at least one ring that has atoms of atleast two different elements as members of its ring(s), one of which iscarbon, and having the specified number of carbon atoms.

As used herein, when a definition is not otherwise provided, the term“fluoroheteroaryl group” refers to a fluoroheteroaryl group in which atleast one hydrogen atom is replaced with a fluorine atom.

As used herein, when a definition is not otherwise provided, the term“substituted” means including at least one substituent such as a halogen(F, Cl, Br, I), hydroxyl, amino, thiol, carboxyl, carboxylate, ester(including acrylates, methacrylates, and lactones), amide, nitrile,sulfide, disulfide, nitro, C₁₋₂₀ alkyl, C₁₋₂₀ cycloalkyl (includingadamantyl), C₁₋₂₀ alkenyl (including norbornenyl), C₁₋₂₀ alkoxy, C₂₋₂₀alkenoxy (including vinyl ether), C₆₋₃₀ aryl, C₆₋₃₀ aryloxy, C₇₋₃₀alkylaryl, or C₇₋₃₀ alkylaryloxy.

When a group containing a specified number of carbon atoms issubstituted with any of the groups listed in the preceding paragraphs,the number of carbon atoms in the resulting “substituted” group isdefined as the sum of the carbon atoms contained in the original(unsubstituted) group and the carbon atoms (if any) contained in thesubstituent. For example, when the term “substituted C₁-C₂₀ alkyl”refers to a C₁-C₂₀ alkyl group substituted with C₆-C₃₀ aryl group, thetotal number of carbon atoms in the resulting aryl substituted alkylgroup is C₇-C₅₀.

As used herein, when the definition is not otherwise provided, the term“mixture” refers to any combination of the ingredients constituting theblend or mixture without regard to a physical form.

Disclosed herein is a photoacid generator compound having Formula (I):

In Formula (I), EWG may be an electron-withdrawing group, which groupthat draws electron density from neighboring atoms towards itself by aresonance effect, an inductive effect, a hyperconjugation effect, or acombination thereof. EWG may be a weakly electron-withdrawing group,such as halogen, a moderately electron-withdrawing, such as aldehyde(—CHO), ketone (—COR), carboxylic acid (—CO₂H), ester (—CO₂R), or amide(—CONH₂), or a strongly deactivating group, such as trihalide (—CF₃,CCl₃), cyano (—CN), sulfone (—SO₂R), sulfonate (—SO₃H), or nitro (—NO₂).For example, EWG may be an electron-withdrawing group selected from —CN,—NO₂, —C(═O)R²¹, C(O)OR²², and —SO₂R²³, wherein R²¹, R²², or R²³ areeach independently a C₁₋₃₀ aliphatic organic group, a C₆₋₃₀ aromaticorganic group, or a C₁₋₃₀ heteroaromatic organic group. In anembodiment, EWG may be a cyano group.

In Formula (I), Y may be a linker connecting group R with the anioniccenter. Y may be a single bond or a linking group. The linking group mayinclude carbon, and may optionally include one or more heteroatoms. Inan example, Y may be a single bond, a C₁₋₃₀ linking group, an ethergroup, a carbonyl group, an ester group, a carbonate group, an aminegroup, an amide group, a urea group, a sulfate group, a sulfone group, asulfoxide group, an N-oxide group, a sulfonate group, a sulfonamidegroup, or a combination of at least two of the foregoing. In anotherexample, Y may be a C₁₋₃₀ linking group optionally including aheteroatom containing O, S, N, F, or a combination of at least one ofthe foregoing heteroatoms. In still another example, Y may be a singlebond, —C(R³⁰)₂—, —N(R³¹)—, —O—, —S—, —S(═O)₂—, —C(═O)—, or a combinationthereof, wherein each R³⁰ and R³¹ is independently hydrogen or a C₁₋₆alkyl group.

In Formula (I), R may be hydrogen, a straight chain or branched C₁₋₂₀alkyl group, a straight chain or branched C₂₋₂₀ alkenyl group, amonocyclic or polycyclic C₃₋₂₀ cycloalkyl group, a monocyclic orpolycyclic C₃₋₂₀ cycloalkenyl group, a monocyclic or polycyclic C₃₋₂₀heterocycloalkyl group; a monocyclic or polycyclic C₃₋₂₀heterocycloalkenyl group; a monocyclic or polycyclic C₆₋₂₀ aryl group,or a monocyclic or polycyclic C₁₋₂₀ heteroaryl group, each of whichexcept hydrogen may be substituted or unsubstituted. In an embodiment, Rmay be a bulky hydrocarbon group, such as a substituted or unsubstitutedpolycyclic C₃₋₂₀ cycloalkyl group.

In Formula (I), M⁺ may be an organic cation, for example, an organicsulfonium cation or an organic iodonium cation having Formula (VII):

In Formula (VII), R⁰ may be a C₁₋₂₀ alkyl group, a C₁₋₂₀ fluoroalkylgroup, a C₃₋₂₀ cycloalkyl group, a C₃₋₂₀ fluorocycloalkyl group, a C₂₋₂₀alkenyl group, a C₂₋₂₀ fluoroalkenyl group, a C₆₋₃₀ aryl group, a C₆₋₃₀fluoroaryl group, a C₁₋₃₀ heteroaryl group, a C₇₋₃₀ aralkyl group, aC₇₋₃₀ fluoroaralkyl group, a C₂₋₃₀ heteroaralkyl group, or a C₂₋₃₀fluoroheteroaralkyl group, each of which is substituted orunsubstituted, and

Ar is a C₆₋₃₀ substituted aromatic organic group,

wherein Ar is optionally connected to R⁰.

In an embodiment, the photoacid generator compound may be represented byFormulae (II) and (III):

Formula (II) may be represented by the following resonance Formulae(IIa) and (IIb):

While not wishing to be bound by theory, it is understood that thenegative charge in the anion of Formula (II) is stabilized by the doublebond and is delocalized between carbon atoms bearing groups X¹, X² andX³, X⁴, respectively.

In Formula (II), X¹, X², X³ and X⁴ may each independently be anelectron-withdrawing group selected from —F, —CN, —NO₂, —C(═O)R²⁴,—C(═O)OR²⁵, —SO₂R²⁶, and CR_(f), wherein R²⁴, R²⁵, and R²⁶ may eachindependently be a C₁₋₃₀ aliphatic organic group, a C₆₋₃₀ aromaticorganic group, or a C₁₋₃₀ heteroaromatic organic group, and R_(f) may bea C₁-C₃₀ fluoroalkyl group.

In Formula (II), R may be hydrogen, a straight chain or branched C₁₋₂₀alkyl group, a straight chain or branched C₂₋₂₀ alkenyl group, amonocyclic or polycyclic C₃₋₂₀ cycloalkyl group, a monocyclic orpolycyclic C₃₋₂₀ cycloalkenyl group, a monocyclic or polycyclic C₃₋₂₀heterocycloalkyl group; a monocyclic or polycyclic C₃₋₂₀heterocycloalkenyl group; a monocyclic or polycyclic C₆₋₂₀ aryl group,or a monocyclic or polycyclic C₁₋₂₀ heteroaryl group, each of whichexcept hydrogen may be substituted or unsubstituted. In an embodiment, Rmay be a bulky hydrocarbon group, such as a substituted or unsubstitutedpolycyclic C₃₋₂₀ cycloalkyl group, which may or may not contain fusedcyclic rings. When the polycyclic C₃₋₂₀ cycloalkyl group contains fusedcyclic rings, the polycyclic C₃₋₂₀ cycloalkyl group may be derived froma caged hydrocarbon, such as adamantane. Thus, in an embodiment, R¹ maybe a substituted or unsubstituted adamantyl group, for example, ahydroxyadamantyl group.

In another embodiment, R may be a polymerizable group such as a C₂₋₂₀alkenyl group. When linker Y includes an oxycarbonyl group —C(═O)O—, thephotoacid generator may contain an acrylate or a methacrylate moiety.

In Formula (II), Y may be a linker connecting group R with the anioniccenter. Y may be a single bond or a linking group. The linking group mayinclude carbon, and may optionally include one or more heteroatoms. Inan example, Y may be a single bond, a C₁₋₃₀ linking group, an ethergroup, a carbonyl group, an ester group, a carbonate group, an aminegroup, an amide group, a urea group, a sulfate group, a sulfone group, asulfoxide group, an N-oxide group, a sulfonate group, a sulfonamidegroup, or a combination of at least two of the foregoing. In anotherexample, Y may be a C₁₋₃₀ linking group optionally including aheteroatom containing O, S, N, F, or a combination of at least one ofthe foregoing heteroatoms. In still another example, Y may be a singlebond, —C(R³⁰)₂—, —N(R³¹)—, —O—, —S—, —S(═O)₂—, —C(═O)—, or a combinationthereof, wherein each R³⁰ and R³¹ is independently hydrogen or a C₁₋₆alkyl group.

Each “

” represents a partial double bond.

The photoacid generator having Formula (I) may have the followingstructures:

wherein L is an organic substituent and M⁺ is an organic cation.

The photoacid generator having Formula (I) may include no halogen atoms.

Specific examples of PAGs having Formula (II) are shown below:

The photoacid generators of the present invention may be covalentlybound to a polymer, wherein the polymer contains one or more acidsensitive structural units. Thus, an embodiment provides anacid-sensitive polymer, which is a polymerization product of thephotoacid generator compound. For an ionic acid generator, either cationor anion components may be covalently linked to a polymer.Alternatively, both the cation and the anion components may becovalently bound to the polymer.

For instance, the photoacid generator anion component may include apolymerizable group (such as acrylate, methacrylate, vinyl ether) whichcan be reacted with a pre-formed polymer, or other monomers, to providea polymer-bound acid generator. Exemplary polymerizable photoacidgenerator anion components include the following structures:

In another embodiment, the photoacid generator may be represented byFormula (III):

In Formula (III), X⁵ and X⁶ may each independently be an oxygen atom oran electron withdrawing group selected from divalent groups C(CN)₂,C(NO₂)₂, C(COR²⁷)₂, C(CO₂R²⁸)₂, C(SO₂R²⁹)₂, and C(R_(f))₂, wherein R_(f)is a C₁-C₃₀ fluoroalkyl group.

Y, R, and M may be the same as in Formula (I) above.

Z¹ and Z² may each independently be hydrogen, a straight chain orbranched C₁₋₅₀ alkyl group, a monocyclic or polycyclic C₃₋₅₀ cycloalkylgroup, a monocyclic or polycyclic C₃₋₅₀ heterocycloalkyl group; amonocyclic or polycyclic C₆₋₅₀ aryl group, a monocyclic or polycyclicC₅₋₂₀ heteroaryl group, or a combination thereof. Groups Z¹ and Z² maybe optionally connected to each other to form a ring.

In Formula (III),

X⁵ and X⁶ may each be C(CN)₂;

R may be hydrogen; and

Y may be a single bond.

At least one of R, Z¹, and Z² may include a polymerizable group such asa C₂₋₂₀ alkenyl group. When linker Y includes an oxycarbonyl group—C(═O)O—, the photoacid generator may contain an acrylate or amethacrylate moiety.

Examples of photoacid generators represented by Formula (III) mayinclude the following compounds:

In Formula (III), when R is hydrogen, Y is a single bond, Z¹ and Z² areconnected together to form C₅₋₂₀ monocyclic or polycyclic aliphatic oraromatic group, a photoacid generator having Formula (III) may berepresented by Formula (IV):

In Formula (IV), X⁵ and X⁶ may be the same as in Formula (III) and R¹may be a halogen, an electron-withdrawing group such as a nitro group, acyano group, a sulfonyl group, or a fluorine atom, a C₁₋₁₀ alkyl group,a C₁₋₁₀ fluoroalkyl group, a C₁₋₁₀ alkoxy group, a C₁₋₁₀ fluoroalkoxygroup, a C₃₋₁₀ cycloalkyl group, a C₃₋₁₀ fluorocycloalkyl group, a C₃₋₁₀cycloalkoxy group, a C₃₋₁₀ fluorocycloalkoxy group, or anelectron-withdrawing group selected from NO₂, CN, C(R_(f))₃ or CO₂R,wherein R_(f) is a C₁-C₃₀ fluoroalkyl group; and k may be an integer of0, 1, 2, 3, or 4.

Examples of photoacid generators represented by Formula (IV) are shownbelow:

Formulae (I), (II), (III), and (IV) all include a cation M⁺, which maybe an organic cation. For example, M⁺ may be an organic sulfonium cationor an organic iodonium cation having Formula (VII).

Specific examples of the organic iodonium cation may be:

In an embodiment, M⁺ may be an organic sulfonium cation having Formula(V):

wherein, each R² is independently a C₁₋₂₀ alkyl group, a C₁₋₂₀fluoroalkyl group, a C₃₋₂₀ cycloalkyl group, a C₃₋₂₀ fluorocycloalkylgroup, a C₂₋₂₀ alkenyl group, a C₂₋₂₀ fluoroalkenyl group, a C₆₋₂₀ arylgroup, a C₆₋₂₀ fluoroaryl group, a C₁₋₂₀ heteroaryl group, a C₇₋₂₀aralkyl group, a C₇₋₂₀ fluoroaralkyl group, a C₂₋₂₀ heteroaralkyl group,or a C₂₋₂₀ fluoroheteroaralkyl group, each of which is substituted orunsubstituted,

wherein each R² is either separate or connected to the other group R²via a single bond or a linking group to form a ring, and

Ar is a substituted or unsubstituted C₆₋₃₀ aromatic organic group.

In another embodiment, M⁺ may be an organic cation having Formula (VI):

wherein

-   -   X is I or S;    -   each R³ is independently a halogen, —CN, —OH, a C₁₋₁₀ alkyl        group, a C₁₋₁₀ fluoroalkyl group, a C₁₋₁₀ alkoxy group, a C₁₋₁₀        fluoroalkoxy group, a C₃₋₁₀ cycloalkyl group, a C₃₋₁₀        fluorocycloalkyl group, a C₃₋₁₀ cycloalkoxy group, or a C₃₋₁₀        fluorocycloalkoxy group;    -   each n is an integer of 0, 1, 2, 3, 4, and 5, provided that when        X is I, at least one n is not 0; and    -   m is an integer of 2 or 3, provided that when X is I, m is 2,        and where X is S, m is 3. In this embodiment, an iodonium cation        requires that at least one substituent is present at the        aromatic ring.

In still another embodiment, M⁺ may be an organic cation having Formulae(VII) or (VIII):

wherein

R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ are each independently a halogen, —CN,—OH, a C₁₋₁₀ alkyl group, a C₁₋₁₀ fluoroalkyl group, a C₁₋₁₀ alkoxygroup, a C₁₋₁₀ fluoroalkoxy group, a C₃₋₁₀ cycloalkyl group, a C₃₋₁₀fluorocycloalkyl group, a C₃₋₁₀ cycloalkoxy group, or a C₃₋₁₀fluorocycloalkoxy group, each of which except a halogen, —CN, and —OHmay be substituted or unsubstituted;

J is a single bond or a connecting group selected from S, O, and C═O,

p is each independently an integer of 0, 1, 2, 3, or 4;

r is an integer of 0, 1, 2, 3, 4, and 5, and

s and t are each independently an integer of 0, 1, 2, 3, and 4.

R³ in Formula (VI), R⁶ and R⁷ in Formula (VII), and R⁸, R⁹ and R¹⁰ inFormula (VIII) may optionally comprise an acid cleavable group, forexample, a C₆₋₁₀ alkoxycarbonylalkyleneoxy group. An example of a C₆₋₁₀alkoxycarbonylalkyleneoxy group is t-butyloxycarbonylmethoxy group asshown in the following compounds:

The present inventive concept provides photoacid generators that includenew methide type anions. Unlike known methide anions that aresubstituted with three electron-withdrawing perfluorosulfonyl groups,methides of this disclosure include one or more electron-withdrawingsubstituents and at least one functional substituent. The functionalsubstituent is designed to impart specific structural and physicalfeatures that are not present in known methide structures. For example,the new design allows the substitution of the methide anion with 193nanometer (nm) transparent and bulky cycloaliphatic groups, suchadamantanyl (adamantyl) or substituted adamantanyl (for example,hydroxyadamantyl). Incorporating bulky cycloaliphatic groups in PAGanions enhances miscibility of the corresponding PAG with 193 nm typepolymer matrix and leads to slower diffusion during lithographicprocessing. The inventive concept allows functionalization of methideanion with a polymerizable group. Notably, known methide anions in theart are limited to (R_(f)SO₂)₃C⁻ electron withdrawing substituent(wherein R_(f) is a fluoroalkyl group). The present inventive conceptallows the substitutions with a wide range of electron-withdrawinggroup, including fluorine-free electron-withdrawing groups.

The generated photoacids are expected to possess high activation energyof diffusion during lithographic processing due to the strongnon-bonding interaction of the photoacid functional groups with otherphotoresist components. For instance, the nitrogen atom of electronwithdrawing cyano group is prone to hydrogen bonding with variety ofhydrogen bond donor groups which are present on the photoresist matrix.

The photoacid generator may be formulated with or combined with acopolymer and a solvent to form a photoresist composition. Where thecombination is a polymer bound photoacid generator, an appropriatelyfunctionalized photoacid generator can be copolymerized with one or moremonomers to form the copolymer, or the photoacid generator can begrafted onto the copolymer.

A copolymer useful for forming a photoresist in combination with thephotoacid generator disclosed herein may include an acid-deprotectable(acid-sensitive) monomer, a base-soluble monomer, a dissolution ratemodifying monomer, and an etch resistant monomer. Any such monomers orcombinations of monomers suitable for forming, for example, a 193 nmphotoresist polymer. In an embodiment, a combination of monomers may beused, which include a (meth)acrylate monomer having anacid-deprotectable base soluble group, a (meth)acrylate monomer having alactone functional group, a (meth)acrylate monomer having a base-solublegroup, or a combination including at least one of the foregoingmonomers. Other monomers, such as (meth)acrylate monomer for improvingadhesion, etch resistance, and so on, may also be included.

Any acid-deprotectable monomer useful for forming a 193 nm photoresistpolymer may be used. Exemplary acid-deprotectable monomers include, butare not limited to:

or a combination comprising at least one of the foregoing monomers,wherein R^(a) is H, F, CN, C₁₋₁₀ alkyl, or C₁₋₁₀ fluoroalkyl.

Any lactone-containing monomer useful for forming a 193 nm photoresistpolymer may be used. Exemplary lactone-containing monomers include, butare not limited to:

or a combination including at least one of the foregoing monomers,wherein R^(a) is H, F, CN, a C₁₋₁₀ alkyl group, or a C₁₋₁₀ fluoroalkylgroup.

Any base-soluble monomer useful for forming a 193 nm photoresist polymermay be used. Exemplary additional base-soluble (meth)acrylate monomersinclude, but are not limited to:

or a combination including at least one of the foregoing monomers,wherein R^(a) is H, F, CN, a C₁₋₁₀ alkyl group, or a C₁₋₁₀ fluoroalkylgroup, and R^(c) is a C₁₋₄ perfluoroalkyl group.

The polymer may also include other monomers, including cage-structuredmonomers for enhancing etch resistance, with or without functionalgroups for improving adhesion. An exemplary adhesion-improving monomermay include:

or a combination comprising the foregoing and at least one additionalmonomer, wherein R^(a) is H, C₁₋₆ alkyl, or CF₃.

The photoacid generator may be combined with the copolymer, either inadmixture, by copolymerization or both, to form a photoresist. Thephotoresist may optionally further include a second acid sensitivepolymer and/or photoacid generator, an amine or an amide additive toadjust photospeed and/or acid diffusion, a solvent, and a surfactant.

The second acid-sensitive polymer may be any polymer suitable forformulating photoresists for use at 193 nm. Such acid-sensitive polymersmay include an acid sensitive polymer including acid sensitive groupsand lactone-containing groups, wherein the deprotection of the acidsensitive group on exposure to acid releases a base-soluble group. Theacid-sensitive polymer may be a polymer-bound photoacid generator (PBP)wherein the photoacid generator repeat unit is an anion or a cation.

The photoresist composition may further include an amine or amidecompound, referred to herein as a quencher. Quenchers may more broadlyinclude, for example, compounds which are hydroxides, carboxylates,amines, imines, and amides. In an embodiment, a useful quencher is anamine, an amide, or a combination comprising at least one of theforegoing. For example, such quenchers may include C₁₋₃₀ organic amines,imines, or amides, or may be a C₁₋₃₀ quaternary ammonium salt of astrong base (for example, a hydroxide or alkoxide) or a weak base (forexample, a carboxylate). Exemplary quenchers may include amines such asTroger's base, a hindered amine such as diazabicycloundecene (DBU) ordiazabicyclononene (DBN), N-protected amines such asN-t-butylcarbonyl-1,1-bis(hydroxymethyl)-2-hydroxyethylamine(TBOC-TRIS), or ionic quenchers including quaternary alkyl ammoniumsalts such as tetrabutylammonium hydroxide (TBAH) or tetrabutyl ammoniumlactate.

Other components of the photoresist may include solvents andsurfactants.

Solvents generally suitable for dissolving, dispensing, and coating thecomponents may include anisole, alcohols including ethyl lactate, methyl2-hydroxybutyrate (HBM), 1-methoxy-2-propanol (also referred to aspropylene glycol methyl ether, PGME), and 1-ethoxy-2 propanol, estersincluding n-butylacetate, 1-methoxy-2-propyl acetate (also referred toas propylene glycol methyl ether acetate, PGMEA),methoxyethoxypropionate, ethoxyethoxypropionate, andgamma-butyrolactone, ketones including cyclohexanone and 2-heptanone,and a combination comprising at least one of the foregoing solvents.

Surfactants may include fluorinated and non-fluorinated surfactants, andmay, for example, be non-ionic. Exemplary fluorinated non-ionicsurfactants may include perfluoro C₄ surfactants such as FC-4430 andFC-4432 surfactants, available from 3M Corporation; and fluorodiols suchas POLYFOX PF-636, PF-6320, PF-656, and PF-6520 fluorosurfactants fromOmnova.

The photoacid generator may be present in the photoresist in an amountof 0.01 to 20 percent by weight (wt %), for example, 0.1 to 15 wt %,based on the total weight of solids. Where a polymer bound photoacidgenerator is used, the polymer bound photoacid generator as thecorresponding monomer is present in the same amount. The copolymer maybe present in an amount of 50 to 99 wt %, for example, 55 to 95 wt %, inanother example, 60 to 90 wt %, and in still another example, 65 to 90wt % based on the total weight of solids. It will be understood that theterm “polymer” used in this context of a component in a photoresist maymean only the copolymer disclosed herein, or a combination of thepolymer with another polymer useful in a photoresist. A surfactant maybe included in an amount of 0.01 to 5 wt %, for example, 0.1 to 4 wt %,and in another example, 0.2 to 3 wt %, based on the total weight ofsolids. A quencher may be included in a relatively small amount of forexample, from 0.03 to 5 wt % based on the total weight of solids. Otheradditives such as embedded barrier layer (EBL) materials for immersionlithography applications may be included in amounts of less than orequal to 30 wt %, for example, less than or equal to 20%, or in anotherexample, less than or equal to 10%, based on the total weight of solids.The total solids content for the photoresist composition may be 0.5 to50 wt %, for example, 1 to 45 wt %, and in another example, 2 to 40 wt%, and still in another example, 5 to 35 wt %, based on the total weightof solids and solvent. It will be understood that the solids may includea copolymer, a photoacid generator, a quencher, a surfactant, and anyoptional additives, exclusive of solvent.

The photoresist composition disclosed herein may be used to form a filmcomprising the photoresist composition, where the film on the substrateconstitutes a coated substrate. Such a coated substrate may include: (a)a substrate having one or more layers to be patterned on a surfacethereof; and (b) a layer of the photoresist composition over the one ormore layers to be patterned. For example, patterning may be carried outusing ultraviolet radiation at wavelength of less than 248 nm, and inparticular, at 193 nm. The patternable film thus includes the photoacidgenerator of Formula (I).

A method of forming an electronic device therefore includes: (a)applying a layer of a photoresist composition on a substrate; (b)patternwise exposing the photoresist composition layer to activatingradiation; and (c) developing the exposed photoresist composition layerto provide a resist relief image. For example, the radiation is 193 nmor 248 nm radiation.

Substrates may be of any dimension and shape, and may, for example, bethose useful for photolithography, such as silicon, silicon dioxide,silicon-on-insulator (SOI), strained silicon, gallium arsenide, coatedsubstrates including those coated with silicon nitride, siliconoxynitride, titanium nitride, tantalum nitride, ultrathin gate oxidessuch as hafnium oxide, metal or metal coated substrates including thosecoated with titanium, tantalum, copper, aluminum, tungsten, alloysthereof, and combinations thereof. For example, the surfaces ofsubstrates herein include critical dimension layers to be patternedincluding, for example, one or more gate-level layers or other criticaldimension layer on the substrates for semiconductor manufacture. Suchsubstrates may, for example, include silicon, SOI, strained silicon, andother such substrate materials, formed as circular wafers havingdimensions such as, for example, 200 mm, 300 mm, or larger in diameter,or other dimensions useful for wafer fabrication production.

The present inventive concept is further illustrated by the followingexamples. All compounds and reagents used herein are availablecommercially except where a procedure is provided below.

EXAMPLES Example 1

Photoacid generator PAG 1 is prepared according to the synthetic schemeoutlined in Synthesis Scheme 1.

A solution of malononitrile (10.00 grams (g), 151 millimoles (mmol)),1-(trimethoxymethyl)adamantane (18.19 g, 76 mmol), and pyridine (5.99 g,76 mmol) is heated under reflux for 20 minutes (min). The reactionmixture is cooled to room temperature. Under agitation, the reactionmixture is charged with dichloromethane (200 milliliters (mL)),triphenylsulfonium bromide (23.38 g, 68 mmol), and deionized water (100mL). The mixture is stirred at room temperature for 16 h. The organicphase is separated and is washed with three 100 mL volumes of deionizedwater. Removing the solvent under vacuum produces triphenylsulfonium2-adamantyl-1,1,3,3-tetracyanopropenide (PAG 1) (36.70 g, 100% yield).

Example 2

Photoacid generator PAG-2 is prepared according to the synthetic schemeoutlined in Synthesis Scheme 2.

The synthesis of the starting material2-methoxy-1,1,3,3-tetracyanopropenide is described in J. Am. Chem. Soc.1958, 80, 2795. Sodium 2-methoxy-1,1,3,3-tetracyanopropenide (10.00 g,51.5 mmol) is dissolved in methanol (100 mL) and adamantylmethylamine(8.51 g, 51.5 mmol) is added thereto. The reaction mixture is heatedunder reflux for two hours and cooled to ambient temperature. Thesolvent is removed under vacuum. To the residual solidtriphenylsulfonium bromide (15.91 g, 46.4 mmol), dichloromethane (150mL), and deionized water (75 mL) are added. The mixture is stirred for16 hours. The organic phase is separated and washed with three 75 mLvolumes of deionized water. The solvent is removed under vacuum to givetriphenylsulfonium 2-adamantylmethylamino-1,1,3,3-tetracyanopropenide(PAG 2) (26.34 g, 100% yield).

Example 3

Photoacid generator PAG 3 is prepared by the synthetic scheme outlinedin Scheme 3.

The starting material1,3-bis(dicyanomethylene)-2,3-dihydro-1H-inden-2-ide ammonium isprepared according to literature procedure (J. Org. Chem., 2013, 78(3),1014) and is mixed with equimolar amount of triphenylsulfonium bromidein a mixture of water/methylene chloride 1/1 by volume. The mixture isstirred for 16 hours. The organic phase is separated and washed withthree times with deionized water. The solvent is removed under vacuum togive PAG 3.

Example 4

Photoacid generator PAG 4 is prepared by the synthetic scheme outlinedin Scheme 4.

The starting material1,3-bis(dicyanomethylene)-2,3-dihydro-1H-inden-2-ide ammonium isprepared according to literature procedure (J. Org. Chem., 2013, 78(3),1014) and is mixed with equimolar amount of di-(4-t-butylphenyl)iodoniumacetate in a mixture of water/methylene chloride 1/1 by volume. Themixture is stirred for 16 hours. The organic phase is separated andwashed with three times with deionized water. The solvent is removedunder vacuum to give PAG 4.

Example 5: Lithographic Evaluation

The photoacid generators are evaluated lithographically according to thefollowing procedure. Photoresists are formulated using the componentsand proportions shown in Table 1. The commercial photoresist polymer A2is used in all examples. Polymer A2 is a pentapolymer incorporatingmonomers M1, M2, M3, M4, and M5 shown below, where the mole percentageof M1/M2/M3/M4/M5 is 20/20/30/20/10 for a total of 100 mole percent ofmonomers. The molecular weight (Mw) of the polymer was 8,000 grams permole (g/mol). The PAG, base (t-butyloxycarbonyl-4-hydroxypyridine,TBOC-4HP), and surface leveling agent (surfactant) PF 656, availablefrom Omnova, are in weight percent based on 100% solids content, withthe balance of the solids being the polymer. The solvents used in theseformulations are PGMEA (S1) and HBM (S2). The final content of solids inboth examples were 4 percent by weight (wt %). The weight ratio ofsolvent S1:S2 in the final formulation was 1:1. Photoresist formulationcompositions for Comparative Example and Examples A, B and C are shownin Table 1 below:

TABLE 1 PAG Base SLA Sample PAG (wt %) (wt %) (wt %) ComparativeTriphenylsulfonium 9.56 1.03 0.1 Example perfluorobutane- sulfonateExample A PAG 1 9.18 1.03 0.1 Example B PAG 2 9.68 1.03 0.1 Example CPAG 3 8.56 1.03 0.1

The above photoresists were lithographically processed as follows. Thephotoresist was spin coated onto a 200 millimeter (mm) silicon waferhaving 84 nm of an organic antireflective coating (AR™77, Dow ElectronicMaterials) and baked at 110° C. for 60 seconds, to form a resist film100 nm in thickness. The photoresist was exposed with ArF excimer laser(193 nm) through a mask pattern targeting a line and space pattern (L/Spattern) having a line width of 90 nm and a pitch of 180 nm, using anArF exposure apparatus ASML-1100 (manufactured by ASML), NA (numericalaperture)=0.75 under annular illumination with outer/inner sigma of0.89/0.64 with focus offset/step 0.10/0.05. The wafers were postexposure baked (PEB) at 100° C. for 60 seconds followed by developingwith 0.26 normal (N) aqueous tetramethylammonium hydroxide (TMAH)developer and subsequent water wash.

In each example, an L/S pattern having a line width of 90 nm and a pitchof 180 nm was formed. Mask Error Factor (MEF) and Exposure Latitude (EL)were determined by processing the image captured by top-down scanningelectron microscopy (SEM) using a Hitachi 9380 CD-SEM, operating at anaccelerating voltage of 800 volts (V), probe current of 8.0 picoamperes(pA), using 200 K× magnification. Exposure latitude (EL) was defined asa difference in exposure energy to print +/−10% of the target diameternormalized by the sizing energy. Mask Error Factor (MEF) was defined asthe ratio of CD change on the resolved resist pattern to the relativedimension change on the mask pattern.

The results from the lithographic evaluation of the above photoresistformulations shows that Examples B, C and D, which utilizes the PAG 1,PAG 2 and PAG 3 respectively, show the improved lithographic performanceof greater exposure latitude, and improved mask error factor.

While this disclosure has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

The invention claimed is:
 1. A photoacid generator compound havingFormula (I):

wherein: EWG is an electron-withdrawing group selected from the groupconsisting of a halogen, —CF₃, —CCl₃, —CN, —NO₂, —C(═O)R²¹, —C(═O)OR²²,—C(═O)NH₂, —SO₃H, and —SO₂R²³, wherein R²¹ is a hydrogen, a C₆₋₃₀aromatic organic group, or a C₁₋₃₀ heteroaromatic organic group, and R²²and R²³ are each independently a hydrogen, a C₁₋₃₀ aliphatic organicgroup, a C₆₋₃₀ aromatic organic group, or a C₁₋₃₀ heteroaromatic organicgroup; Y is a single bond, a C₁₋₃₀ linking group, an ether group, acarbonyl group, an ester group, a carbonate group, an amine group, anamide group, a urea group, a sulfate group, a sulfoxide group, anN-oxide group, a sulfonate group, a sulfonamide group, or a combinationof at least two of the foregoing; R is hydrogen, a straight chain orbranched C₁₋₂₀ alkyl group, a straight chain or branched C₂₋₂₀ alkenylgroup, a monocyclic or polycyclic C₃₋₂₀ cycloalkyl group, a monocyclicor polycyclic C₃₋₂₀ cycloalkenyl group, a monocyclic or polycyclic C₃₋₂₀heterocycloalkyl group; a monocyclic or polycyclic C₃₋₂₀heterocycloalkenyl group; a monocyclic or polycyclic C₆₋₂₀ aryl group,or a monocyclic or polycyclic C₁₋₂₀ heteroaryl group, each of whichexcept hydrogen is substituted or unsubstituted; and M⁺ is an organicsulfonium cation or an organic iodonium cation having Formula (VII):

wherein, R⁰ is a C₁₋₂₀ alkyl group, a C₁₋₂₀ fluoroalkyl group, a C₃₋₂₀cycloalkyl group, a C₃₋₂₀ fluorocycloalkyl group, a C₂₋₂₀ alkenyl group,a C₂₋₂₀ fluoroalkenyl group, a C₆₋₃₀ aryl group, a C₆₋₃₀ fluoroarylgroup, a C₁₋₃₀ heteroaryl group, a C₇₋₃₀ aralkyl group, a C₇₋₃₀fluoroaralkyl group, a C₂₋₃₀ heteroaralkyl group, or a C₂₋₃₀fluoroheteroaralkyl group, each of which is substituted orunsubstituted, and Ar is a C₆₋₃₀ substituted aromatic organic group,wherein Ar is optionally connected to R⁰.
 2. A photoacid generatorcompound having Formulae (II) or (III):

wherein: X¹, X², X³ and X⁴ are each independently anelectron-withdrawing group; X⁵ and X⁶ are each independently an electronwithdrawing group selected from C(CN)₂, C(NO₂)₂, C(COR²⁷)₂, C(CO₂R²⁸)₂,C(SO₂R²⁹)₂, and C(R_(f))₂, wherein R_(f) is a C₁-C₃₀ fluoroalkyl group;Z¹ and Z² are each independently hydrogen, a straight chain or branchedC₁₋₅₀ alkyl group, a monocyclic or polycyclic C₃₋₅₀ cycloalkyl group, amonocyclic or polycyclic C₃₋₅₀ heterocycloalkyl group; a monocyclic orpolycyclic C₆₋₅₀ aryl group, a monocyclic or polycyclic C₅₋₂₀ heteroarylgroup, or a combination thereof, wherein groups Z¹ and Z² are optionallyconnected to each other to form a ring; Y is a single bond or a C₁₋₃₀linking group; R is a straight chain or branched C₁₋₂₀ alkyl group, astraight chain or branched C₂₋₂₀ alkenyl group, a monocyclic orpolycyclic C₃₋₂₀ cycloalkyl group, a monocyclic or polycyclic C₃₋₂₀cycloalkenyl group, a monocyclic or polycyclic C₃₋₂₀ heterocycloalkylgroup; a monocyclic or polycyclic C₃₋₂₀ heterocycloalkenyl group; amonocyclic or polycyclic C₆₋₂₀ aryl group, or a monocyclic or polycyclicC₁₋₂₀ heteroaryl group, each of which except hydrogen is substituted orunsubstituted; and M⁺ is an organic sulfonium cation or an organiciodonium cation having Formula (VII):

wherein, R⁰ is a C₁₋₂₀ alkyl group, a C₁₋₂₀ fluoroalkyl group, a C₃₋₂₀cycloalkyl group, a C₃₋₂₀ fluorocycloalkyl group, a C₂₋₂₀ alkenyl group,a C₂₋₂₀ fluoroalkenyl group, a C₆₋₃₀ aryl group, a C₆₋₃₀ fluoroarylgroup, a C₁₋₃₀ heteroaryl group, a C₇₋₃₀ aralkyl group, a C₇₋₃₀fluoroaralkyl group, a C₂₋₃₀ heteroaralkyl group, or a C₂₋₃₀fluoroheteroaralkyl group, each of which is substituted orunsubstituted, and Ar is a C₆₋₃₀ substituted aromatic organic group,wherein Ar is optionally connected to R⁰; and each “

” represents a partial double bond.
 3. A photoacid generator compoundhaving Formula

wherein, X⁵ and X⁶ are each C(CN)₂; Z¹ and Z² are each independentlyhydrogen, a straight chain C₁₋₅₀ alkyl group, a branched C₃₋₅₀ alkylgroup, a monocyclic C₃₋₅₀ cycloalkyl group, a polycyclic C₇₋₅₀cycloalkyl group, a monocyclic or polycyclic C₃₋₅₀ heterocycloalkylgroup; a monocyclic C₆₋₅₀ aryl group, a polycyclic C₁₀₋₅₀ aryl group, amonocyclic or polycyclic C₅₋₂₀ heteroaryl group, or a combinationthereof, wherein groups Z¹ and Z² are optionally connected to each otherto form a ring; R is a polycyclic C₃₋₂₀ cycloalkyl group; Y is a singlebond, —C(R³⁰)₂—, —N(R³¹)—, —O—, —S—, —S(═O)₂—, —C(═O)—, or a combinationthereof, wherein each R³⁰ and R³¹ is independently hydrogen or a C₁₋₆alkyl group; and M⁺ is an organic sulfonium cation or an organiciodonium cation having Formula (VII):

wherein, R⁰ is a C₁₋₂₀ alkyl group, a C₁₋₂₀ fluoroalkyl group, a C₃₋₂₀cycloalkyl group, a C₃₋₂₀ fluorocycloalkyl group, a C₂₋₂₀ alkenyl group,a C₂₋₂₀ fluoroalkenyl group, a C₆₋₃₀ aryl group, a C₆₋₃₀ fluoroarylgroup, a C₁₋₃₀ heteroaryl group, a C₇₋₃₀ aralkyl group, a C₇₋₃₀fluoroaralkyl group, a C₂₋₃₀ heteroaralkyl group, or a C₂₋₃₀fluoroheteroaralkyl group, each of which is substituted orunsubstituted, and Ar is a C₆₋₃₀ substituted aromatic organic group,wherein Ar is optionally connected to R⁰.
 4. The photoacid generatorcompound of claim 2, wherein in Formula (III): X⁵ and X⁶ are eachC(CN)₂; and Y is a single bond.
 5. A photoacid generator compound havingFormula (IV):

wherein, X⁵ and X⁶ are each independently an electron withdrawing groupselected from C(NO₂)₂, C(COR²⁷)₂, C(CO₂R²⁸)₂, C(SO₂R²⁹)₂, and C(R_(f))₂,wherein R²⁷, R²⁸, and R²⁹ are each independently a C₁₋₃₀ aliphaticorganic group, a C₆₋₃₀ aromatic organic group, or a C₁₋₃₀ heteroaromaticorganic group, and wherein R_(f) is a C₁-C₃₀ fluoroalkyl group; M⁺ is anorganic sulfonium cation, or M⁺ is an organic iodonium cation havingFormula (VII):

wherein, R⁰ is a C₁₋₂₀ alkyl group, a C₁₋₂₀ fluoroalkyl group, a C₃₋₂₀cycloalkyl group, a C₃₋₂₀ fluorocycloalkyl group, a C₂₋₂₀ alkenyl group,a C₂₋₂₀ fluoroalkenyl group, a C₆₋₃₀ aryl group, a C₆₋₃₀ fluoroarylgroup, a C₁₋₃₀ heteroaryl group, a C₇₋₃₀ aralkyl group, a C₇₋₃₀fluoroaralkyl group, a C₂₋₃₀ heteroaralkyl group, or a C₂₋₃₀fluoroheteroaralkyl group, each of which is substituted orunsubstituted, and Ar is a C₆₋₃₀ substituted aromatic organic group,wherein Ar is optionally connected to R⁰; R¹ is a halogen, a C₁₋₁₀ alkylgroup, a C₁₋₁₀ fluoroalkyl group, a C₁₋₁₀ alkoxy group, a C₁₋₁₀fluoroalkoxy group, a C₃₋₁₀ cycloalkyl group, a C₃₋₁₀ fluorocycloalkylgroup, a C₃₋₁₀ cycloalkoxy group, a C₃₋₁₀ fluorocycloalkoxy group, or anelectron-withdrawing group selected from NO₂, CN, C(R_(f))₃ or CO₂R,wherein R_(f) is a C₁-C₃₀ fluoroalkyl group; and k is an integer of 0,1, 2, 3, or
 4. 6. The photoacid generator compound of claim 1, whereinthe organic sulfonium cation has Formula (V):

wherein, each R² is independently a C₁₋₂₀ alkyl group, a C₁₋₂₀fluoroalkyl group, a C₃₋₂₀ cycloalkyl group, a C₃₋₂₀ fluorocycloalkylgroup, a C₂₋₂₀ alkenyl group, a C₂₋₂₀ fluoroalkenyl group, a C₆₋₂₀ arylgroup, a C₆₋₂₀ fluoroaryl group, a C₁₋₂₀ heteroaryl group, a C₇₋₂₀aralkyl group, a C₇₋₂₀ fluoroaralkyl group, a C₂₋₂₀ heteroaralkyl group,or a C₂₋₂₀ fluoroheteroaralkyl group, each of which is substituted orunsubstituted, wherein each R² is either separate or connected to theother group R² via a single bond or a linking group, and Ar is asubstituted or unsubstituted C₆₋₃₀ aromatic organic group.
 7. Thecompound of claim 1, wherein M⁺ is an organic cation having Formula(VI):

wherein X is I or S; each R³ is independently a halogen, a C₁₋₁₀ alkylgroup, a C₁₋₁₀ fluoroalkyl group, a C₁₋₁₀ alkoxy group, a C₁₋₁₀fluoroalkoxy group, a C₃₋₁₀ cycloalkyl group, a C₃₋₁₀ fluorocycloalkylgroup, a C₃₋₁₀ cycloalkoxy group, a C₃₋₁₀ fluorocycloalkoxy group, or aC₆₋₁₀ alkoxycarbonylalkyleneoxy group; each n is an integer of 0, 1, 2,3, 4, and 5, provided that when X is I, at least one n is not 0; and mis an integer of 2 or 3, provided that when X is I, m is 2, and where Xis S, m is
 3. 8. The compound of claim 1, wherein M⁺ is an organiccation having Formulae (VII) or (VIII):

wherein R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, and R¹⁰ are each independently ahalogen, —CN, —OH, a C₁₋₁₀ alkyl group, a C₁₋₁₀ fluoroalkyl group, aC₁₋₁₀ alkoxy group, a C₁₋₁₀ fluoroalkoxy group, a C₃₋₁₀ cycloalkylgroup, a C₃₋₁₀ fluorocycloalkyl group, a C₃₋₁₀ cycloalkoxy group, or aC₃₋₁₀ fluorocycloalkoxy group, each of which except a halogen, —CN, and—OH is substituted or unsubstituted; J is a single bond or a connectinggroup selected from S, O, and C═O, p is each independently an integer of0, 1, 2, 3, or 4; r is an integer of 0, 1, 2, 3, 4, and 5, and s and tare each independently an integer of 0, 1, 2, 3, and
 4. 9. Anacid-sensitive polymer comprising a unit formed from a photoacidgenerator compound having Formula (I):

wherein: EWG is an electron-withdrawing group selected from the groupconsisting of a halogen, —CF₃, —CCl₃, —CN, —NO₂, —C(═O)R²¹, —C(═O)OR²²,—C(═O)NH₂, —SO₃H, and —SO₂R²³, wherein R²¹ is a hydrogen, a C₆₋₃₀aromatic organic group, or a C₁₋₃₀ heteroaromatic organic group, and R²²and R²³ are each independently a hydrogen, a C₁₋₃₀ aliphatic organicgroup, a C₆₋₃₀ aromatic organic group, or a C₁₋₃₀ heteroaromatic organicgroup; Y is a single bond, a C₁₋₃₀ linking group, an ether group, acarbonyl group, an ester group, a carbonate group, an amine group, anamide group, a urea group, a sulfate group, a sulfoxide group, anN-oxide group, a sulfonate group, a sulfonamide group, or a combinationof at least two of the foregoing; R is a polymerizable group; and M⁺ isan organic sulfonium cation or an organic iodonium cation having Formula(VII):

wherein, R⁰ is a C₁₋₂₀ alkyl group, a C₁₋₂₀ fluoroalkyl group, a C₃₋₂₀cycloalkyl group, a C₃₋₂₀ fluorocycloalkyl group, a C₂₋₂₀ alkenyl group,a C₂₋₂₀ fluoroalkenyl group, a C₆₋₃₀ aryl group, a C₆₋₃₀ fluoroarylgroup, a C₁₋₃₀ heteroaryl group, a C₇₋₃₀ aralkyl group, a C₇₋₃₀fluoroaralkyl group, a C₂₋₃₀ heteroaralkyl group, or a C₂₋₃₀fluoroheteroaralkyl group, each of which is substituted orunsubstituted, and Ar is a C₆₋₃₀ substituted aromatic organic group,wherein Ar is optionally connected to R⁰.
 10. A photoresist composition,comprising: an acid-sensitive polymer, a solvent, and the photoacidgenerator compound of claim
 1. 11. A photoresist composition,comprising: the acid-sensitive polymer of claim 9, and a solvent.
 12. Amethod of forming an electronic device, comprising: (a) applying a layerof the photoresist composition of claim 10 on a substrate; (b)patternwise exposing the photoresist composition layer to activatingradiation; and (c) developing the exposed photoresist composition layerto provide a resist relief image.